Apply check-defs.sh to -icu and -subset, toward mingw fix (#780)

diff --git a/src/gen-def.py b/src/gen-def.py
index ad1606e..1673537 100755
--- a/src/gen-def.py
+++ b/src/gen-def.py
@@ -9,8 +9,11 @@
 	if h.endswith (".h"):
 		with io.open(h, encoding='utf8') as f: headers_content.append (f.read ())
 
-result = ("EXPORTS\n" +
-	"\n".join (sorted (re.findall (r"^hb_\w+(?= \()", "\n".join (headers_content), re.M))) +
-	"\nLIBRARY libharfbuzz-0.dll")
+result = """EXPORTS
+%s
+LIBRARY lib%s-0.dll""" % (
+	"\n".join (sorted (re.findall (r"^hb_\w+(?= \()", "\n".join (headers_content), re.M))),
+	sys.argv[1].replace ('.def', '')
+)
 
 with open (sys.argv[1], "w") as f: f.write (result)